mishoo/UglifyJS2 — pull request #580 by caridy (2014-11-11 19:43:16+00:00)
Title: using the original sourcemap as the base

As today, if the original source map is provided, the generator was still ruling the transformations of the source, instead we should create the generator from the original map when needed. More information about this feature here:

* https://github.com/mozilla/source-map#sourcemapgeneratorfromsourcemapsourcemapconsumer